Software Engineering Introduction
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Transcript of Software Engineering Introduction
Alliance University, [email protected] 2
Software ?
● Countries depends on softwares.● Today we are moving foward towards pervasive
computing.● Idea <--> Software● Software contributed in space programs● Sofware delivers the most important product of
our time-”information”.
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Define
● “Software is :– (i) instructions that when executed provide desired
features , function , and performance; – (ii) data structure that enable the program to
adequately manipulate information, and – (iii) description information in both hard copy and
vitual form that describes the operation and use of the programs”
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Characteristics of Software
● Differences from hardware
– s/w is developed or engineered, it is not manufactured in the classical sense.
– s/w doesn't “wear out.”
– Re-usability.
“Software is logical rather than a physical system element.”
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Fundamental Types
● Fundamental types of software :-– Generic Products
● Stand-alone systems that are produced s/w organization.● Sold on the open market to any customer.
– Customised Products● For particular customer.● Especially developed as per the customer requirement.
● Generic s/w control the s/w specifications.● Organization (buyer) control the s/w specifications
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Further Categories● System software
– Used to service other programs/
● Application software– Solve specific business needs.
● Engineering/Scientific software● Embedded software
– Resides within a product
● Product-line software– Specific capability for use by different customers
● Web application– Network centric softwares
● Artifical intelligence software– It includes intelligence ex, robotics , expert systems etc.
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Good Software Attributes
● Maintainability– It can evolve to meet the change.
● Dependability and security– It includes reliability , security and safety
● Efficiency– Should not waste system resources (memory and
processor cycles)
● Acceptability– It must be understandable , usable and compatible
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Software Process
● Software Process – “It is the set of activities and associated results that
produce a software products”– A framework for the tasks that are required to build
high-quality software.
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Software Process
● Software Specification– In this customer and engineers define the software to be
produced and the constraints on its operation.
● Software Development– The software is designed and programmed
● Software Validation– The system is checked to ensure that it is what the customer
requires.
● Software Evolution– The software is modified to adapt it to changing customer and
market requirement.
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Issues:Software
● Issues that affect many different types of software:-– Heterogeneity
● Systems are distributed systems which includes different types of computer and mobile devices.
– Business and social change● Change is rapid now a days.● Many traditional software engineering techniques are time
consuming.
– Security and trust● Software is intertwined with all aspects of our lives.
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Software Engineering
● What is Software Engineering ?– It is an engineering discipline that is concerned
with all aspects of software production from the early stages of system specifications to maintaining the system after it has gone into use.
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Friedrich Bauer (10 June 1924 – 26 March 2015)● He was a german computer scientist and professor● He was first to propose the widely used stack methods
of expression evalution.● In 1968 , he coined the term “Software Engineering”
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Software Process● A common process framework
is established
● Define small number of framework activities
● A number of task sets – (SE tasks , milestones , work products , SQA points)
● Umberalla Activities
– Software Quality Assurance
– Software Configuration Management (tracking and controlling changes)
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Software Process Activities
● Software Specification– In this customer and engineers define the software to be
produced and the constraints on its operation.
● Software Development– The software is designed and programmed
● Software Validation– The system is checked to ensure that it is what the customer
requires.
● Software Evolution– The software is modified to adapt it to changing customer and
market requirement.
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Software Process Model
● It is a simplified description of a software process that presents one view of the process.
● It includes activities , software products and the roles of people
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Ex:Workflow Model
● Sequence of activities in the process along with their inputs , outputs and dependencies.
● The activities in this model resent human actions.
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Ex:Dataflow/Activity Model
● Represents the process as a set of activities , each of which carries out some data transformation.
● It shows how the input to the process , such as specification , is transformed to an output , such as a design.
● Can be carried by people or by computers.
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Ex:Role/Action Model
● This represents the roles of the people involved in the software process and the activities for which they are responsible
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Software Life Cycle
● Classic Life Cycle– Analysis --> Design --> Coding --> Testing & Support
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Software Process Model:Approach
● Waterfall approach– Takes activities and represents them as separate
process phases (as analysis , designing , development , testing etc.)
– After each stage is defined it is “signed-off”
● Iterative development● Component-based software engineering (CBSE)
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Waterfall
● Waterfall approach– Takes activities and represents them as separate process
phases (as analysis , designing , development , testing etc.)
– After each stage is defined it is “signed-off”
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Iterative Approach
● Iterative Approach
– An initial system is rapidly developed from very abstract specifications
– Then refine with customer input
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CBSE Approach● CBSE Approach
– It assumes that parts of the system already exist
– Focus on integrating these parts rather developing from scratch
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Software Engineering Ethics
● Confidentiality– Employers or clients
● Competence– No misrepresent your level of competence
● Intellectual property rights– Take case of patents and copyright.
● Computer misuse– No misuse other people’s computer.
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ACM/IEEE-CS Joint Task Force on Software Engineering Ethics
● Eight Principles– PUBLIC
● Act in public interest
– CLIENT and EMPLOYER– PRODUCT
● Highest professional standards
– JUDGMENT● Maintain integrity and independence in their professional judgment
– MANAGEMENT● Maintain ethical approach of management
– PROFESSION● Advance the integrity and reputation of the profession consistent
– COLLEAGUES● Fair and supportive of their colleagues
– SELF● Maintain lifelong learning
